This research was carried out on a laboratory scale with stages adapted to the literature so that results could be obtained that could improve the quality of the mortar itself. The limitation of the problem in this research is the use of bagasse ash waste as a cement substitute for mortar mixtures with mixed variations of 0%, 6%, 9% and 12% of the weight of cement, NaCl as a substitute for water, characterization of tests on the mortar mixture which includes testing the compressive strength of the mortar. From the results of research and testing of mortar with various mixtures of bagasse ash as a substitute for fine aggregate and NaCl as a substitute for water, it can be concluded that the compressive strength of normal mortar without bagasse ash waste but using water from NaCl is 1.75 kg/cm2., strong press mortar with waste bagasse ash 6% of the weight of cement and NaCl is 1.44 kg/cm2, the compressive strength of mortar with waste bagasse ash 9% of the weight of cement and NaCl compressive strength is 1.39 kg/cm2, compressive strength of mortar with bagasse ash waste 12% of the cement weight, the compressive strength is 1.55 kg/cm2 which is the optimum mixture content in this mixture. Mortar mixed with bagasse ash and NaCl results in a lower compressive strength than normal mortar.